How often should EANx tanks be analyzed to confirm the gas mix?

It is essential to analyze EANx (enriched air nitrox) tanks before each use or at least every year to confirm the gas mix. This practice ensures that the diver has the correct blend of oxygen and nitrogen for their intended dive profile, reducing the risk of oxygen toxicity and optimizing the dive plan.

Regular analysis helps in identifying any unintended changes in gas composition that may occur over time due to factors like tank handling, environmental conditions, or residual gases remaining after a previous fill. By verifying the gas mix each time the tank is used, divers are better equipped to plan their dives safely and effectively, ensuring they remain within safe limits for the oxygen percentage in the mix according to their planned depth and duration.

Confirming the gas mix annually at a minimum provides a safety buffer but does not adequately address the potential risks between dives when conditions and tank contents could change. This makes the requirement of checking before each use both a best practice and a safety necessity.